Spatial Filter, Three-Axis

The objective lens Z-axis motion is provided by a precision linear bearing, so that focus is found and maintained without jitter or side-play. The long-travel focus adjustment accommodates virtually any objective lens. The open architecture of this spatial filter makes it especially easy to change pinholes and objectives.

The open architecture of this spatial filter makes it especially easy to change pinholes and objectives. The pinhole mount is magnetically registered against the machined faces of the non-rotating X-Y adjustment spindles for easy installation and removal.

Spatial filter alignment is straightforward. Start by positioning the spatial filter assembly in the laser beam while observing the back reflections from the objective lens to bring both into alignment. To align the pinhole, first defocus the lens, then while observing the pinhole substrate, adjust the pinhole position until a faint light appears at the output. Alternate the lens Z-axis adjustment with X-Y pinhole position corrections until the best throughput and focus are achieved. This is indicated when a deliberate pinhole movement causes the symmetric output pattern to quickly disappear. A slow smear means a poor focus.

Three-axis spatial filters come standard with a 25 µm high-energy ultra-thin molybdenum pinhole (900PH-25) pinhole and M-10X microscope objective. This pinhole and objective combination may not be correct for your particular application. Different objective lenses and mounted pinholes can be ordered separately. These spatial filters are designed to accommodate all M- and MV-Series Objective Lenses, the L-4X and L-50X Infinity-Corrected Objective Lenses, and 900PH-Series Mounted Pinholes.